KEY: S = data do not meet publication standards because of high sampling
variability or other reasons.

NOTE FOR DATA ON THIS PAGE: Some unpublished estimates can be derived
from other data published on this table. However, figures obtained in this manner
are subject to these same limitations.

SOURCE FOR DATA ON THIS PAGE: U.S. Department of Transportation, Bureau
of Transportation Statistics and U.S. Department of Commerce, U.S. Census Bureau,
1997 Commodity Flow Survey, Washington, DC: 2000, data from CD-ROM,
CD-EC97-CFS.